<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 600px;
            height: 600px;
            border: 5px solid gray;
            display: grid;
            /* 网格 */
            grid-template-rows: 200px 200px 200px;
            grid-template-columns: 200px 200px 200px;

            grid-template-areas: 'a a c'
                                 'a a c'
                                 'b b b'
            ;
            /* 形状只能为矩形 */

        }
        .box div:nth-child(1){
            grid-area: a;
        }
        .box div:nth-child(2){
            grid-area: c;
        }
        .box div:nth-child(3){
            grid-area: b;
        }
    </style>
</head>
<body>
    <div class="box">
        <div>1</div>
        <div>2</div>
        <div>3</div>
    </div>
</body>
</html>